Kiln



F. FIULER AND 1. G. MAXWELL.

KILN.

APPLICATION HLED Dwz?. i919.

Patented May 25, 1920..

2 SHEETS-SHEET Figl.

F. FIDLER AND J. G. MAXWELL.

KILN.

APPLICATION FILED DEC. 27. 1919.

1,341,550. Patented May 25, 1920.

2 SHEETS-SHEET 2- Fig] m m @I UNITED sTATEs PATENT OFFICE.

FRANCIS FIDLER, OF WIGAN, AND JAMES GRAHAM MAXWELL, OF LONDON, ENGLAND.

KILN.

Application led December 27, 1919.

To all whom t may concern.'

Be it known that we, FRANCIS F IDLER and JAMES' GRAHAM MAXWELL, subjects of the King of Great Britain and Ireland, residing at l/Vivan, Lancashire, England, and London, England, respectively, have invented certain new and useful Improvements 1n Kilns, of which the following is aspecification.

This invention relates to improvements in gas, coal or oil tired continuous kilns of the tunnel and car type. A tunnel and car kiln usually comprises a continuous tunnel through which a train of cars are slowly and continuously passed, the tunnel being divided into three zones, (1) the preheating zone, (2) the burning zone and (3) the cooling zone, the goods or ware on the cars passing through the zones in the order given, emerging from the kiln by the cooling zone.

The' object of the present invention is to enable waste heat radiated by the burnt goods in the cooling Zone to be efficiently absorbed by air currents owing out of contact with the goods, in such a manner that there is no necessity for the cooling tunnel to be larger than that required for the passage of the cars and goods thereon, the small unoccupied space or clearance allowing only such a volume of air to pass as will assist the gradual cooling of the goods, without setting up high velocity currents of cold air in large separate paths alongside the goods which tends to excess of air without economy, and will form a hot air supply to the fires or gas burners, or for other suitable purposes.

In the accompanying drawings Figure 1 is a plan of a tunnelv and car kiln. Fig'. 2 is a side sectional elevation, on a larger scale, of the cooling zone, the section being on the lines X11-XII and II-II Fig. 5. Fig. 3 is a sectional plan in the line III-III Fig. 2. Fig. 4 is a sectional plan the left hand portion being a section in the line :IV-IV Fig. 5, while the right hand portion shows part of the crown broken away to expose the air ducts therein. Fig. 5 is an end sectional elevation on the line V-V Fig. 2. Fig. 6 is an end elevation of the kiln part in section showing the ducts in the crown of the burning zone. Fig. 7 is a sectional plan on the line VII-VII Fig. 6. Fig. 8 is a side eleva# tion of part of another form of cooling zone,

Specification of Letters Patent.

Patented May 25, 1920,

Serial No. 347,669.

Fig. .9 being an end sectional elevation on the line IX--IX Fig. 8. Fig. 10 is a sectional plan the section being taken on the irregular line X-X Fig. 9. Fig. 11 is a sectional plan on the line XI-XI Fig. 9.

The tunnel and car kiln comprises a pre- `heating zone 1, a burning zone 2, and a cool- 4ends by horizontal ducts 8 and 9 respectively. The ducts 7, 8, 9, in each wall thereby provide a continuous zigzag course for cold air introduced by suitable meanssucli as an air supply pipe 10 fitted with a valve 11 and connected by a pipe 12 to a fan 13. The vertical ducts 7 are separated from the interior of the cooling zone 3 by heat absorbers'of heat conductive material, which in the part of the zone where they will withstand the prevailingwheat are 'in the form of cast iron panels 14, whereas in the part nearer to the burning zone 2 they are preferably in the form of firebrick panels 15. The air passing through the ducts 7, 8, 9 in the walls of the cooling zone impinges on the heat absorbers 14,15 extracting therefrom the heat which is radiated to them by the heated ware or goods on the cars' 5 in the cooling zone, which cars travel in the opposite direction to the general direction of travel of the air.

Other air ducts 16, 16 are provided in the roof or crown of the cooling Zone, and these ducts 16 receive air., for instance from pipes 17, 17 tted with valves 18, 18 and connected by the aforesaid pipe 12 to the fan 13. This air extracts heat from the crown of the cooling zone and is led into a series of sinuous ducts 19 in the hollow crown 20 of the burning zone 2, which is at a higher temperature than any other portion of the kiln structure, except the combustion chambers. The air traveling through the highly heated ducts 19 is then driven down through suitable ducts 20 controlled by dampers 22 and thereby supplied to the gas burners of fires in the burning zone, the air being sup-4 The burners or fires may be of any approved type known in the art. In the form of kiln illustrated they are not shown but are assumed to be gas burners the supply of gas for instance producer gas being supplied by gas ducts 21 to the smaller gas ducts 36 leading to the burners.

The air which passes through the ducts 7, 8, 9, in the walls of the cooling zone 3 escapes through pipes 23 fitted with valves 37 and may be utilized in any suitable manner, for instance the pipes 23 may lead it into drying tunnels 24 through which the green goods may be passed on cars. As the warm air thus led into the drying tunnels is clean, not having made contact with .the goods in the cooling zone 3, and not being mixed with the gases of combustion from the `burning zone 2, it may be led into direct contact with the green goods thereby drying them without having any deleterious effect on them. The air and moisture from the drying tunnels 24 is extracted by fans 25 and delivered by pipes 26 to vent shafts 27.

In the form shown in Figs. 8 to 10 the cast iron panels 14 having sloping upper ends 28, and the upper horizontal connecting ducts 9 are formed by arched castings 29 having slopingv sides 30, 31. l

The ducts 7 and 9 communicate with each other by openings 33, and the ducts 7 and 8 by openings 34.

A single air duct 16 may be arranged in the crown of the cooling zone 3, the duct 16 being formed by cast i'ronboxes 32 placed end to end to form a continuous duct. The boxes 32 have sloping sides corresponding to the adjacent sloping sides 31 of the arched castings 29. The boxes 32 thereby act in the manner of key-stones. Air is supplied by a fan 13 through a pipe 12 branching intothree pipes 10, 17, 10.

Asbestos or like heat insulating material 35 is provided against the outer walls of the flues 7 and 8 to avoid conduction of heat to the outside of the kiln.

lnall forms illustrated the panels 14, 15 are flush with the inner surface of the walls of the cooling zone. The arched castings 29 and cast iron boxes 32 similarly present flush surfaces at the crown. Hence there is no necessity for the cooling tunnel or cooling zone 3, to be larger than that required for the passage of the cars and goods thereon, the small unoccupied space or clearance 'allowing only such a volume of air to pass as will assist the gradual cooling of the goods, without setting up high velocity currents of cold air' in large bulk or separate paths of large cross section alongside the goods which tends to excess of air without economy and tends to unequal cooling liable to crack the goods, which has been a common difficulty with tunnel and car kilns as hitherto built. By means of heat absorbers and inclosed air liues as above described a cooling of the interior of the portion of the kiln canal or tunnel, known as the cooling zone is effected efliciently and without setting up conflicting air currents.

VVe claim- 1. A car kiln having a cooling zone, the walls of .such zone being formed with air ducts closed against the interior of said zone, a wall of said ducts open to said zone being of independent material of relatively high heat conductivity.

2. A car kiln having a cooling zone with the walls thereof formed with vertically-arranged spaced channels, the walls of said channels open to the temperature of the zone being of independent material of relatively high heat conductivity, said zone walls being formed with upper and lower substantially horizontal channels alternately connecting one vertical channel to the next, whereby to provide a tortuous air passage in said Zone wall.

3. A car kiln having a cooling zone with the walls thereof formed with vertically-arranged spaced'channels, the` walls of said channels vopen to the temperature of the zone being of independent material of relatively high heat conductivity, said zone walls being formed with upper and lower substantially horizontal channels alternately connecting one vertical channel to the next, whereby to provide a tortuous air passage in said zone wall, and means for drawing air through such air passage.

4. In a tunnel and car kiln, a cooling zone having air ducts in the walls thereof, and another air duct in ther crown thereof, a burning zone having air ducts in the crown thereof connected to the said air duct in the crown ofthe cooling zone, means for passing air through the said ducts in the walls yofthe cooling zone, and means for passing air through the ducts in the crowns of the cooling and burning zones, substantially as and for the purpose hereinbefore set forth.

5. In a tunnel and car kiln, a cooling zone having air ducts in the Walls thereof, a separate air duct in the crown thereof, said1 air ducts in the walls and said air duct in the crown having means made of cast iron for separating said lducts from the interior of the zone, and means for passing air separately through the ducts in the walls and the duct in the crown substantially as and for the purpose hereinbefore set forth.

6. In a tunnel and car kiln, a cooling zone having vertical air ducts in the walls thereof, horizontal ducts in lthe walls alternately at higher and lower levels for connecting said vertical ducts together, said vertical ducts having cast iron panels separating them from the interior of the cooling zone, and said horizontal ducts at the higher level being in the form of arched iron castings, substantially as and for the purpose hereinbefore set forth.

7. In a tunnel and 4car kiln, a cooling zone having vertical air ducts in the Walls thereof, horizontal ducts in said Walls connecting said vertical ducts alternately at their upper and lower ends, said horizontal ducts at the upper ends being in the form of arched castings having sloping sides, a separate duct in the crown of said cooling Zone, in the form of a box casting having sloping sides conforming to the adjacent sloping sides of said arched castings, and means for passing air into all of the aforesaid ducts, substantially as and for the purpose hereinbefore set forth.

8. In a tunnel and car kiln, a cooling Zone having air ducts in the Walls and crown of said zone, heat absorbers of good heat conductive material separating said ducts from the interior ofthe Zone, said heat absorbers being substantially liush with the inner surface of the Walls and crown, and means for passing air through said ducts into contact with said heat absorbers substantially as and for the purpose hereinbefore set forth.

In testimony whereof We have signed our names to this specification in the presence of two subscribing Witnesses.

FRANCIS FIDLER. J. GRAHAM MAXWELL.

Witnesses FREDK. E. SQUIRE, B. CLARK. 

